Clearly, there are large returns to considering jobs that require a few extra hours on the margins, especially since the women in my study recognized that there are ways to work more without sacrificing family time.

About half the moms I spoke with worked “split shifts” -- that is, leaving work at a reasonable time, spending the evening with family, then finishing work up after the kids went to bed. Others worked strategically on weekends.

A few hours on Saturday morning and a few hours on Sunday night leaves most of the weekend free, and means you put in the time while still having a reasonable life during the week.

2. Ask for Forgiveness, Not Permission

Sometimes we think going part time is the best way to combine work and life, but officially cutting hours means officially cutting pay, and probably promotion opportunities too.

High-earning women understand many jobs are more flexible than advertised. About three-quarters of the women in my study did something personal during traditional work hours. They would go volunteer at a preschooler’s class, come into work a little later and make up the time at night.

They focused on results, and figured they’d explain themselves if the issue ever came up. It usually didn’t.

3. Be Strategically Seen

The women in my study were efficient during their time at work, but they also understood that business is never just business.

Advancing in your career requires investing in relationships so people trust you, and want to work for you. Even if you want to spend most of your evenings at home, you could go out with colleagues three times per month. That’s just 10% of the 30 days in a month.

We take breaks at work anyway, whether we intend to or not. Rather than surfing the web for 20 minutes during a low energy spot in the afternoon, grab a colleague and get coffee together.

Make time to mentor by inviting a younger associate to join you for lunch. That’s a much better choice than spending your lunch hour cleaning out your inbox. You’ll never reach the bottom, anyway. It’s futile!

4. Let It Go

The women in my study spent about 10 hours per week on housework and errands. That’s about half the amount of time the average employed woman spends on these tasks. In some cases, it’s because women had outsourced cleaning -- which isn’t affordable for everyone -- but it was just as often a conscious choice to spend time on higher-value economic activities.

If you’re trying to get ahead at work, you’re better off spending the time after the kids go to bed reading industry journals or brainstorming new business ideas than picking up the toys, which will just come out again the next morning.

5. Take Care of Yourself

While we tend to think combining a big career and a family will lead to sleep deprivation, I found that was not the case.

The women in my study slept an average of 54 hours per week. That comes out to just a little bit under eight hours per day. About 90% of the logs featured exercise.

I don’t think this is a fluke. Getting adequate sleep and exercise doesn’t take time. These activities make time in the sense of giving you more energy for everything else you need to do in life.

We all have the same 168 hours in a week, but we don’t all spend them the same way. Make smart choices with those hours, and it’s quite possible to get ahead at work and have a life as well.

Your Turn: Do any of these strategies ring true for you? How do you balance your career with your life?

Laura Vanderkam is the author of I Know How She Does It: How Successful Women Make the Most of Their Time, and other time management books including 168 Hours, and What the Most Successful People Do Before Breakfast. She blogs at www.LauraVanderkam.com.